Concurrent coupling between a particle simulation and a continuum description

Abstract

We introduce a numerical scheme that concurrently couples a particle simulation of a multi-component polymer melt to a continuum description. We use a soft, coarse-grained model in the particle simulation and a time-dependent Ginzburg-Landau approach for the continuum description. The coupling between the particle coordinates and the order-parameter field, m, allows us to estimate the parameters the free-energy functional, F(GL)[m], of the Ginzburg-Landau approach and it makes the particle model follow the time-evolution of the order-parameter field. The algorithm exploits the time-scale separation between the fast kinetics of the order-parameter field and the slow temporal variations of the parameters of the free-energy functional. A detailed analysis is presented for the spinodal decomposition of a binary polymer blend based on the Random-Phase Approximation and Monte-Carlo simulations.